The present invention relates in general to the alignment of optical devices, and more particularly to a method for precisely aligning single or multiple reflectors used in antenna systems operating at RF or visible light frequencies.
Alignment telescopes are currently used to fix the position of several points on a reflector. These point positions are then used to best fit the theoretical surface contour to the measured points, and then to determine the axis of the reflector by calculations. The alignment telescope is then positioned on this axis to position feeds, subreflectors, or other RF devices. Sometimes lasers are also used. In either case, the process is complex, time consuming, and in many cases impractical.
In cases of small reflectors, collimated light beams are used on an optical bench. However, this technique requires highly reflective surfaces which are both expensive and relatively difficult to achieve while maintaining the required RMS surface accuracy.
Optical antennas have been aligned by measuring the peak radio frequency gain relative to the mounting surface in azimuth and elevation. This is a very inaccurate method, but may be acceptable for some low frequency applications. However, this method is inappropriate for alignment of multiple reflectors, i.e., subreflectors and multiple reflectors associated with beam waveguide systems.
It is therefore an object of the present invention to provide an alignment method permitting very accurate alignment between single or multiple reflectors and feeds in high frequency antenna systems.